Hi! Welcome to PC.
Upon reading your post I was strongly reminded of my father, who I feel quite certain had bipolar disorder.
What's difficult for me is that you could very well be describing states of hypomania and states of depression - and, at the end of your post I might think "mixed state" (feeling agitated, but unable to motivate and so on).
And you could also be describing a "normal" you and a "depressed" you.
There are many online tests. Unfortunately, I haven't found a test (or quiz) for BD that I believe thoroughly covers the disorder accurately. But there some that are worth checking out.
What I can say without a doubt is that you are significantly troubled about the moods you experience. For that reason, I strongly encourage you to have an assessment done by a psychiatrist. I truly think doing so would be worth your while.
It's important to remember, too, that seeing a psychiatrist when you're feeling more on the depressed side is important. I say that because when you're feel "up" you might brush off the idea of needing to reach out for help.